Saturated esters of ketone formaldehyde condensation products



I Patented Aug. 30, 1949 SATURATED nsrsns or. KETONE FORM- ALDEHYDECONDENSATION rnonuc'rs Harold Wittcoii, Minneapolis, Minn, assignor toGeneral Mills, Inc., a corporation of Delaware No Drawing. ApplicationOctober 21, 1948, Serial No. 55,840

6 Claims.

\ The present invention relates to the saturated higher fatty acidesters of the ketone formaldehyde condensation products described in mycopending application Serial No.'599,948, filed June 16, 1945, entitledEsters, of which the present application is a continuation-in-part. Thepolyhydroxy condensation products which are contemplated by the presentinvention are those which have at least four hydroxyl groups and whichresult from the condensation of formaldehyde with a ketone having atleast four active hydrogen atoms adjacent the carbonyl group. Theinvention contemplates the esterification of these polyhydroxycondensation products with saturated higher fatty'acids includingsaturated aliphatic acids containing from seven to twentytwo or morecarbon atoms. The invention contemplates the substantially completeesterification of the polyhydroxy compounds with these saturated higherfatty acids, the acids being used either singly or in admixture. Theresultant productsvary from viscous liquids to hard solids dependingupon the higher saturated fatty acids or combination of acids employed.The products find use as plasticizers, waxes, intermediates, and

the like, depending upon their particular physical and/or chemicalcharacteristics.

It is, therefore, a primary object of the present.

invention to provide saturated higher fatty acid,

esters of polyhydroxy, condensation products of formaldehyde andaketone, the condensation products containing at least four hydroxy]groups and being substantially completely esterified with the saturatedhigher fatty acids.

This and other objects of the invention will be more fully apparent fromthe followingdescription of the invention with particular reference tothe examples which are to be considered as illustrative only and not aslimiting the invention.

In general, th invention involves the preparation of esters of saturatedfatty acids of more than seven carbon atoms, of polyhydroxy condensationproducts of formaldehyde with ketones. These saturated esters include awide variety of compounds in view of the variation which is possible inthe ketone used in the condensation, the extent of condensation andaccordingly the number of hydroxyl groups present in the condensationproduct, and the nature of the saturated fatty acids employed foresteriflcation.

The polyhydroxy condensation products employed in the present inventionmay, be derived from any aliphatic or alicyclic ketone which has atleast four active hydrogens adjacent the earbonyl group. Typical ketonesof this type include cyclohexanone, cyclopentanone, acetone, methylethyl ketone, diethyl ketone, diacetyl, acetonylacetone, diacetonealcohol, levulinic acid, and the like. In the preparation of thepolyhydroxy condensation products it is usually preferred to employ atleast one. mole of formaldehyde per mole of active hydrogen in theketone. In those instances in which the ketone is capable-of beingreduced to a secondary alcohol group an additional mole of formaldehydeshould be employed for this purpose. In addition, it is usuallypreferred to employ a slight excess of formaldehyde over thattheoretically required. I

The preparation of some of the condensation products of ketones referredto herein have been recorded in the literature. Apel et al., Ann., 289,46 (1896), and Apel and Toliens, Ben, 2'7, 108! (1894). Improved methodsof preparing these condensation products will be found in the examplesof the present application and in the copending application of thepresent inventor, Serial No. 599,94'l, filed June 16, 1945, entitledCondensation of ketones with formaldehyde, now Patent No. 2,462,031,February 15, 1949. The condensation reaction results in a mixture ofproducts which maybe of varying degrees of hydroxylation and in somecases may be in the form of a syrupy liquid. It will be apparent thatthis mixture of condensation products may be used in that condition foresteriflcation if it is not desired to produce the ester as a purecompound.

If the syrup is not readily crystallizable, and if a pure crystallinecondensation product is desired, it may be obtained in some instances byforming an acetal or ester or other derivative as sulfuric acid, may beadded. As an alternative,

an acetal derivative may be obtained by heating the syrup in aqueousmethanol with an aldehyde such as benzaldehyde and a small amount ofmineral acid for a suitable period of time. The acetal may be isolatedfrom the solution by filtration after which it may be purified bycrystallization from a suitable solvent such as alcohol.

The isolated acetal derivative may be converted to the hydroxy compoundby treatment with a strong acid, such as hydrochloric acid. The vola- 3tile ketone or aldehyde may then be distilled off. leaving the purehydroxy compound as a lightcolored oil which crystallizes readily oncooling. Where the aldehyde liberated is as high boiling asbenzaldehyde, the application of vacuum or the use of steam distillationis desirable.

The esterification with the fatty acid may be accomplished with eitherthe crude syrup or with the isolated pure hydroxy compound. Likewise. itis possible to esterii'y the acetal directly. This may be accomplishedunder the influence of an acid catalyst, preferably oxalic acid as iteffects the least amount of discoloration. Other stron acidic catalysts,such as p-toluenesulionic acid and sulfuric acid, may likewise be usedto catalyze this reaction.

Where the free hydroxy compound is employed in the esterification, anyof the well known processes of the prior art may be employed. Severaladvantageous procedures, however, have been evolved. In one case it hasbeen found possible to obtain excellent products by heating and stirringat around 200 C.. equivalent quantities of the acid and thepolyfunctional alcohol for a period of three to four hours. Thepolyfunctional alcohol, if it is used in a syrupy condition, mayadvantageously be brought into contact with the other reagents bydissolving it in water. During the reaction the water is rapidly drivenoff. The color of the product is improved by the use of an inertatmosphere such as that provided by carbon dioxide or nitrogen whereasthe rate of esterification is accelerated by the employment of a smallamount of catalyst such as the stearates. naphthenates, abietates, orother fat soluble salts of metals such as calcium, cadmium, cerium,strontium, zinc, and the like. Catalysts such as litharge, and those ofan acidic nature such as sulfuric acid and hydrogen chloride, may bevaluable in some cases. Near the end of the reaction the application ofa vacuum is valuable in order to remove the last trace of volatile orunreacted material. Following this general procedure then. it is easilypossible to obtain a product with an acid number and hydroxyl numberlower than 30. If still lower values are desired, heating may becontinued for a longer period of time. In cases where a product isdesired which is completely free of any fatty acid, the material may bedissolved in petroleum ether or naphtha and titrated to neutrality withalcohol caustic. The precipitated soaps may then either be filtered oilor extracted with aqueous ethanol. The product is then recovered fromthe hydrocarbon solution by desolvation. Another process of purificationwhich may be employed when an extremely pure product is desired is thatin which unreacted acid and highly hydroxylated or partially esterifiedalcohol is extracted by the use of ethanol. I Still another method ofesteriflcation whic has been found particularly advantageous is that inwhich a small amount of a hydrocarbon solvent, such as xylene. is usedfor the purpose of removing the water of esterification azeotroplcally.By controlling the amount of solvent employed, the temperature of thereaction mixture may be raised to any desired degree. The advantage ofthis derives from the fact that any water produced is readily removedthus driving the reaction in the desired direction.

The esterification may likewise be accomplished azeotropically by theuse of high boiling hydrocarbon solvent such as the isomerictriisopropylbenzenes in sufficient quantity to keep .4 the solublereactants and products in solution. Here again an azeotrope is formedwith the water of esteriflcation. This, however, is not as satisfactoryas the use of a small amount of solvent such as xylene since it requiresthe use of a large amount of solvent which because of its low volatilityis more difiicult to remove at the end of a reaction. In either case theapparatus may be arranged so that the azeotropes distill in such amanner that the water is separated in the distillate and the hydrocarbonisreturned to the reaction vessel.

The esters may be obtained also by a transesterlfication reactionbetween the polyhydric alcohol and a glyceride such as soybean orlinseed oil or other esters of saturated or unsaturated higher fattyacids. Here again, an elevated temperature and stirring are advisabletogether with the use of catalysts such as oil soluble salts of calcium.strontium, barium, zinc, lithium, and the like. The esters may also beprepared by any of the other methods of esterification commonly used inthe art.

The acids which are used for esteriflcation include all the saturatedfatty acids having seven or more carbon atoms up to twenty-two andhigher. Such acids include capric, lauric. myristic, palmitic, stearic,arachidic and behenic acids. The physical and chemical properties of theresultant products depend upon the particular fatty acids employed. Ingeneral the esters which are produced from lauric acid and from shorterchain saturated fatty acids are liquid products and find their principalutility as plasticizers. Those derived from palmitic and longer chainsaturated fatty acids are solid in nature and are excellent waxes. Thesesolid products are also useful as plasticizers. Variations in thephysical properties between these extremes are possible by varying thefatty acids and by emplaying mixtures.

These esters are compatible with a wide variety of resins and cellulosederivaties which they serve to plasticize, soften, elasticize,lubricate, and

, otherwise modify. The resulting compositions may be molded underpressure, kneaded or milled on differential rolls or mixers, dissolvedin solvents to form coating compositions, extruded to form ribbons,fibers, or other structural shapes, emulsified or otherwise fabricatedinto useful compositions.

The solid products may be varied so as to simulate natural waxes such asbeeswax and carnauba wax or any properties intermediate the propertiesof these two natural waxes. Furthermore the wax compositions of thepresent invention are compatible with the common natural waxes such asparafiin, montan, carnauba, beeswax, ceresin, and similar waxes. Thusblends can be made to suit specific purposes. The present waxes can alsobe blended with such diverse substances as rosin, bentonite, metallicnaphthenates, metallic stearates, and the like. Moreover, the waxycompounds of the present invention are soluble in inexpensive coal-tarhydrocarbons and petroleum distillates. and yield gels with thesesolvents, which gels are valuable in the formulation of wax compositionssuch as paste and polishing waxes. The waxes can be emulsified by any ofthe usual emulsifying agents such as amine or hydroxyamine soap, and theemulsions are capable of holding large quantities of water.

The following examples will serve to illustrate the invention.

Example 1 In} an appropriate vessel equipped with agitatorgand refluxcondenser was placed 392 Par s f cyclohexanone, 660 parts offormaldehyde in the form of paraformaldehyde, 3500 parts of water, and112 parts of calcium oxide. With stirring .the temperature of thesolution rose spontaneously to 55 C. whereupon the exothermic nature ofthe reaction was checked by external cooling. Thereafter the reactionmixture was heated and stirred at 50-55 C. for two hours. The reactionmixture after having been acidified to Congo red paperwith dilutesulfuric acid was filtered and desolvate'd to yield a syrup whichcrystallized readily on trituration with alcohol. Crystallization fromabsolute ethanol yielded a product melting at 130-431 C. whose structureis indicated by I.

HOHlC CHQOH of the polyhydric alcohol was added in order to provide anazeotropic solvent for removal of the water of reaction. The

apparatus was the same as that described in Ex ample 2. The reactionmixture was heated rapidly to 165 C., after which the temperature wasraised to 205 C. during a period of one hour. During the second hour ofheating, the temperature was raised to 225 C. and thereafter slowly to235 C. A total reaction time of 8 hours was employed whereupon thexylene was removed in vacuo. There resulted a light colored viscousliquid with an acid number of 11.3 and a hydroxyl number of 16.0.

' Example 4 ;A mixture of 52.5 parts of2,2,6,6-tetramethyiolcyclohexanol and 200 parts of lauric acid wasreacted in thepresence of a, catalytic amount of lead stearate (1.6parts). As in the previous examples, xylene .was used as an azeotropicsolvent, and the esterification was carried out in the apparatusdescribed in Example 2. Thereaction mixture was heated to 165 C.,whereupon thetemperature was raised to 208 C. over a period of one hourand to 235 C. during the second hour. The total reaction time was 8hours, and the product which resulted was a very viscous liquid at roomtemperature. It solidified when immersed in ice water and showed atendency cohol to yield a hard, white wax which melted-at 59 C. Thesaponification equivalent of 311 (cal-- culated 310.5) and the lowhydroxyl number of 6 indicated that the product was the pentastearate of2,2,6,6-tetramethylolcyclohexanol. This material possessed verydesirable wax-like properties particularly because of its extremehardness and pleasing light color.

Example 2 A mixture of 55 parts of 2,2,6,6-tetramethylolcyclohexanol wasreacted with 280 parts of commercial grade stearic acid. ing 1.6 partsof lead stearate was used, and the esterification was carried outazeotropica lly'employing xylene as the'azeotropic solvent. The reactionproceeded with continuous stirring. The

reaction flask was equipped with a Dean stark tube whichallowed thewater of reaction to colnol.

lect at the bottom of the tube, whereas the xylene returned to thereaction mixture. The reaction mixture was heated rapidly to 180 C.Thereafter the temperature was allowed to reach 235 C. over a period of75 minutes. The temperature was maintained at 235 C. for a totalreaction time of 6.5.hou'r's. The xylene was removed to obtain a white,homogeneous product which possessed an acid number of 4.5, a hydroxylnumber of 5.5, and consisted primarily of the pentastearate of2,2,6,6-tetramethylolcyclohexa- The product had a ball and ring meltingpoint of 43 C. This product is capable of further purification byprecipitating it from a hot solution of alcohol.

Example 3 A mixture of 52.5 parts of 2,2,6,6-tetramethylolcyclohexancland 144 parts of technical caprylto acid was reacted in the presence of1.6 parts of lead stearate as'a catalyst. Fifty parts of'xylene Acatalyst compris- I to solidify at room temperature after long standmg iExample 5 In a vessel equipped with an agitator and a reflux condenserwas placed 116 parts of acetone, 480 parts of formaldehyde in the formof paraformaldehyde and 1700 parts of water. Thereafter 56 parts ofcalcium oxide was added with stirring. The reaction mixture thereuponwas heated to 50 C. whereupon external heating was discontinued. Theexothermic nature of the reaction caused the temperature to rise to 90C. whereupon the reaction: mixture was cooled to room temperature. Ifdesired, the same effect may be attained by maintaining the reactionmixture at a temperature'of 50-55 C. for one to three hours. Thesolution thereupon was treated with dilute sulfuric acid until it wasbarely acid to Congo red indicator. Oxalic acid solution was added tomake the reaction mixture strongly acid to Congo red indicator and toprecipitate the last traces of calcium ion. The easily filtrableprecipitate of calcium sulfate and calcium oxalate was removed whereuponthe aqueous solution was evaporated in vacuo.. The almost water-whitesyrup which resulted was treated with an organic solvent such as benzeneand again evaporated in vacuo, the benzene serving to remove occludedwater azeotropically. The

syrup which resulted had a hydroxyl content of 28-30% and contained asubstantial amount of an anhydroenneaheptitol which may be moreaccurately described as tetrahydro-3,3,5,5-tetrakis (hydroxymethyl)-4-pyranol.

A mixture of '75 parts of the condensation product, 144 parts ofcommercial caprylic acid and 1.6 parts of lead stearate was esterifiedazeotropically in the presence of xylene in the apparatus described inExample 2. The reaction mixture was heated to C. and thereafter wasallowed to reach C. over a period of one hour. During the second hourthe reaction temperature reached 235 C. and was maintained there for atotal reaction time of 8 hours. Upon removal of the xylene thereresulted a light colored, very viscous droxyl number of 2.5.

trample 8 In an appropriate vessel was placed 2'88-pa rts and 280 partsof commercial acidwas es- I termed in the presence of 1.6 parts of leadstearate of methyl ethyl ketone, 780 parts of formaldehyde asparaformaldehyde and 3000 parts of water.

There was added slowly with stirring 112 parts of calcium oxidewhereupon the temperature rose spontaneously to 50 C. Thereafter coolingwas employed so that the temperature would not rise higher and once theinitial exothermic reaction had subsided, the reaction mixture washeated and stirred at 50-55 C. for two hours. The product was worked upas described in Example 5 for the condensation product of acetone andformaldehyde to yield an almost colorless syrup whose hydroxyl contentwas of the order of 30%. Because of the procedure used to remove thecalcium ion the product was acidic in nature. This acidity could inlarge part be removed by the use of a basic ion exchange resin such asAmberlite IR-4. The syrupy product was used in the form of an aqueoussolution for esteriflcation purposes. The high hydroxyl content of theproduct together with certain other analytical investigations leads tothe conclusion that the product is analogous to the one obtained fromacetone whereupon the structure of the chief constituent may bepostulated as desoxyanhydroenneaheptito], II.

CHIOH CHs The tetralaurate was prepared by reacting 75 parts of thecondensation product with 200 parts of lauric acid in the presence of acatalyst comprising 1.6 parts of lead stearate. The reaction was carriedout azeotropically using xylene as the azeotropic solvent. The apparatuswas similar to that described in Example 2. The reaction mixture washeated to 140 C. after which the reaction temperature was raised to 190C. over a period of one hour. By the end of the second hour the reactiontemperature had reached 235 C. The temperature was maintained here foreight hours whereupon the solvent was removed. A viscous liquid resultedwith an acid number of 13 and a hydroxyl content of 0.

Ezample 7 1 A mixture of '15 parts of the condensation product of methylethyl ketone and formaldehyde whichserved a s a catalyst. The reactionwas carried out azeotropically with the apparatus described in Example2. The reaction mixture was heated to C. after which it was allowed torise to 235 C. slowly over a period of two hours. The reaction mixturewas maintained at 235 C. for a total reaction time of eight hours. Theproduct was a hard, white wax with an acid number of 16.4, a hydroxylnumber oi. 12.5, and a ball and ring melting point of 455 C. Furtherpurification could be eiiected by allowing the product toprecipitatefrom hot alcohol.

While various modifications of the invention have been described, it isto be understood that other variations are possible without departingfrom the spirit thereof.

I claim as my invention:

1. An ester of a 'polyhydroxy condensation product having at least fourhydroxyl groups. said polyhydroxy condensation product resulting fromthe condensation of formaldehyde and a ketone having at least fourreplaceable hydrogen atoms adjacent the carbonyl group. in which themolal ratio of formaldehyde to ketone is not substantially less than onemole of formaldehyde per mole of active hydrogen in the ketone, saidcondensation product being substantially completely esterifled withpredominantly saturated higher fatty acids.

2. 2,2,6,6-tetramethylolcyclohexanol substantially completely esterifiedwith a higher saturated fatty acid.

3. Tetrahydro 3,3,5,5 tetrakis (hydroxymethyD-4-pyranol substantiallycompletely estermed with a higher saturated fatty acid.

4. Tetrahydro-3,3,5-tris (hydroxymethyl) 5- methyl-4-pyranolsubstantially completely esterified with a higher saturated faty acid.

5. Pentastearate of-22.6.6-tetramethylolcyclohexanol.

6. Tetrastearate of tetrahydro 3,3,5-tris-(hydroxymethyl)-5-methyl-4-pyranol.

HAROLD WI'ITC OFF.

REFERENCES crran The following references are of record in the file ofthis patent:

